Phase 6: replace app template with the vet sample domain + jobs slice, pipelines and worker

- templates/app now carries the vet server (parents/pets/treatments/vets/appointments)
- added domain/jobs slice with /jobs OpenAPI paths and Job schema (x- extensions)
- added pipelines/shared scaffold (loader, ports, registry) and the
  appointment_reminder family; worker.py dispatches jobs by kind
- wired init.py, config.py worker knobs, .env.example, docker-compose worker
- unit tests for jobs routes, the pipeline family and worker dispatch (12 passing)

standards/src/templates/app/.gitignore

@@ -15,6 +15,9 @@ venv/
 # Generated wire contract (regenerate from openapi.yaml)
 _gen/
 
+# Uploads
+uploads/
+
 # Packaging / coverage
 dist/
 build/